Aspects of the invention relate to a semiconductor module with semiconductor chips at different supply potentials, and to a method for the production thereof. One of the semiconductor chips has electrodes on its top side and a rear side electrode. Furthermore, the semiconductor component has a control chip, wherein the electrodes of the semiconductor chip have a larger area than the signal and supply electrodes on the top side of the control chip.
Large area or larger area is understood in this context to mean that power supply electrodes or power output electrodes of the semiconductor chip cover virtually an entire side of the semiconductor chip and are provided for a high, for example vertical, current-carrying. By contrast, small-area control electrodes, which transmit for example signals for controlling the power semiconductor chip or for clocking to a circuit node provided in the semiconductor module, take up only a fraction of a side of a semiconductor chip. In this case, it is characteristic of power semiconductor chips of the MOSFET type or of the IGBT type that a power output electrode and a control electrode are arranged on a common top side and a power supply electrode is arranged on a rear side as rear side electrode of the power semiconductor chip.
For driving the semiconductor chip, for example, in an on-board electrical supply system, integrated circuits are used as gate driver. Such a control chip with an integrated circuit, which chip requires a different supply potential relative to the semiconductor chip, can be fixed and wired as a stacked control chip on the top side of a power semiconductor chip. For this purpose, the control chip can be adhesively bonded onto the top side of the power semiconductor chip by a non-conductive medium. Such a “chip-on-chip construction” has the following disadvantages:
1. the areal extent of the control chip is limited to the areal extent of the top side of the power semiconductor chip;
2. the design of the top side of the power semiconductor chip must be adapted for the stacked control chip;
3. there is the risk of damage to the power semiconductor chip in the region of the adhesive joint;
4. there is the risk of impairing the bonding areas of the electrodes on the top side of the power semiconductor chip due to the electrically insulating adhesive;
5. the height of the semiconductor chip stack must be considerably smaller than the maximum thickness of the plastic housing composition above the semiconductor chip island.
The document DE 197 16 674 A1 provides, as semiconductor module, a semiconductor device having at least two semiconductor chips arranged on semiconductor chip islands separate from one another in each case, such that they can be at different potentials. This solution has the disadvantage that, for the application of different potentials, no standardized leadframe with a single central semiconductor chip island can be used and expensive special fabrications have to be provided for leadframes. Such semiconductor modules have such unfavourable external contact arrangements or “footprints” that the redistribution wiring outlay by virtue of corresponding conductor track routing on a superordinate circuit board is considerable and requires board area, which is disadvantageous for compact applications for current and voltage supply in on-board electrical supply systems and/or in mobile radio devices with AC/DC and/or DC/DC converters.
For these and other reasons, there is a need for the present invention.